Not sure how common an issue it is, mine measured 6 11/16" to the pan rail at the front and was about 1/16" lower at the rear (only parallel to the pan rails in 1 plane).
I would say their quality control could definately be improved upon. Make sure you have a good look at the pan before installing it too.
You could send it back and hope they send you a better (taller) one or bend it to give the right clearance. You need a fair bit of heat in it to bend that pipe which destroys the gold plating - but no one's going to be looking at it when it's done.
Mine is also the 18650, the pictures on summit/mancini ect are just generic photos.
Or they have recently changed the design for this part number.
It fits with the factory/mopar windage tray.